pp-trace User's Manual
:program:`pp-trace` is a standalone tool that traces preprocessor activity. It's also used as a test of Clang's PPCallbacks interface. It runs a given source file through the Clang preprocessor, displaying selected information from callback functions overridden in a PPCallbacks derivation. The output is in a high-level YAML format, described in :ref:`OutputFormat`.
pp-trace Usage
Command Line Format
pp-trace [<pp-trace-options>] <source-file> [-- <front-end-options>]
<pp-trace-options> is a place-holder for options
specific to pp-trace, which are described below in
:ref:`CommandLineOptions`.
<source-file> specifies the source file to run through the preprocessor.
<front-end-options> is a place-holder for regular
Clang Compiler Options,
which must follow the <source-file>.
Command Line Options
pp-trace Output Format
The pp-trace output is formatted as YAML. See https://yaml.org/ for general YAML information. It's arranged as a sequence of information about the callback call, including the callback name and argument information, for example::
--- - Callback: Name Argument1: Value1 Argument2: Value2 (etc.) ...
With real data::
--- - Callback: FileChanged Loc: "c:/Clang/llvm/clang-tools-extra/test/pp-trace/pp-trace-include.cpp:1:1" Reason: EnterFile FileType: C_User PrevFID: (invalid) (etc.) - Callback: FileChanged Loc: "D:/Clang/llvm/clang-tools-extra/test/pp-trace/pp-trace-include.cpp:5:1" Reason: ExitFile FileType: C_User PrevFID: "D:/Clang/llvm/clang-tools-extra/test/pp-trace/Input/Level1B.h" - Callback: EndOfMainFile ...
In all but one case (MacroDirective) the "Argument" scalars have the same name as the argument in the corresponding PPCallbacks callback function.
Callback Details
The following sections describe the purpose and output format for each callback.
Click on the callback name in the section heading to see the Doxygen documentation for the callback.
The argument descriptions table describes the callback argument information displayed.
The Argument Name field in most (but not all) cases is the same name as the callback function parameter.
The Argument Value Syntax field describes the values that will be displayed for the argument value. It uses an ad hoc representation that mixes literal and symbolic representations. Enumeration member symbols are shown as the actual enum member in a (member1|member2|...) form. A name in parentheses can either represent a place holder for the described value, or confusingly, it might be a literal, such as (null), for a null pointer. Locations are shown as quoted only to avoid confusing the documentation generator.
The Clang C++ Type field is the type from the callback function declaration.
The description describes the argument or what is displayed for it.
Note that in some cases, such as when a structure pointer is an argument value, only some key member or members are shown to represent the value, instead of trying to display all members of the structure.
FileChanged Callback
FileChanged is called when the preprocessor enters or exits a file, both the top level file being compiled, as well as any #include directives. It will also be called as a result of a system header pragma or in internal renaming of a file.
Argument descriptions:
| Argument Name | Argument Value Syntax | Clang C++ Type | Description |
|---|---|---|---|
| Loc | "(file):(line):(col)" | SourceLocation | The location of the directive. |
| Reason | (EnterFile|ExitFile|SystemHeaderPragma|RenameFile) | PPCallbacks::FileChangeReason | Reason for change. |
| FileType | (C_User|C_System|C_ExternCSystem) | SrcMgr::CharacteristicKind | Include type. |
| PrevFID | ((file)|(invalid)) | FileID | Previous file, if any. |
Example::
- Callback: FileChanged Loc: "D:/Clang/llvm/clang-tools-extra/test/pp-trace/pp-trace-include.cpp:1:1" Reason: EnterFile FileType: C_User PrevFID: (invalid)
FileSkipped Callback
FileSkipped is called when a source file is skipped as the result of header guard optimization.
Argument descriptions:
| Argument Name | Argument Value Syntax | Clang C++ Type | Description |
|---|---|---|---|
| ParentFile | ("(file)" or (null)) | const FileEntry | The file that #included the skipped file. |
| FilenameTok | (token) | const Token | The token in ParentFile that indicates the skipped file. |
| FileType | (C_User|C_System|C_ExternCSystem) | SrcMgr::CharacteristicKind | The file type. |
Example::
- Callback: FileSkipped ParentFile: "/path/filename.h" FilenameTok: "filename.h" FileType: C_User
FileNotFound Callback
FileNotFound is called when an inclusion directive results in a file-not-found error.
Argument descriptions:
| Argument Name | Argument Value Syntax | Clang C++ Type | Description |
|---|---|---|---|
| FileName | "(file)" | StringRef | The name of the file being included, as written in the source code. |
| RecoveryPath | (path) | SmallVectorImpl<char> | If this client indicates that it can recover from this missing file, the client should set this as an additional header search patch. |
Example::
- Callback: FileNotFound FileName: "/path/filename.h" RecoveryPath:
InclusionDirective Callback
InclusionDirective is called when an inclusion directive of any kind (#include</code>, #import</code>, etc.) has been processed, regardless of whether the inclusion will actually result in an inclusion.
Argument descriptions:
| Argument Name | Argument Value Syntax | Clang C++ Type | Description |
|---|---|---|---|
| HashLoc | "(file):(line):(col)" | SourceLocation | The location of the '#' that starts the inclusion directive. |
| IncludeTok | (token) | const Token | The token that indicates the kind of inclusion directive, e.g., 'include' or 'import'. |
| FileName | "(file)" | StringRef | The name of the file being included, as written in the source code. |
| IsAngled | (true|false) | bool | Whether the file name was enclosed in angle brackets; otherwise, it was enclosed in quotes. |
| FilenameRange | "(file)" | CharSourceRange | The character range of the quotes or angle brackets for the written file name. |
| File | "(file)" | const FileEntry | The actual file that may be included by this inclusion directive. |
| SearchPath | "(path)" | StringRef | Contains the search path which was used to find the file in the file system. |
| RelativePath | "(path)" | StringRef | The path relative to SearchPath, at which the include file was found. |
| Imported | ((module name)|(null)) | const Module | The module, whenever an inclusion directive was automatically turned into a module import or null otherwise. |
Example::
- Callback: InclusionDirective IncludeTok: include FileName: "Input/Level1B.h" IsAngled: false FilenameRange: "Input/Level1B.h" File: "D:/Clang/llvmnewmod/clang-tools-extra/test/pp-trace/Input/Level1B.h" SearchPath: "D:/Clang/llvmnewmod/clang-tools-extra/test/pp-trace" RelativePath: "Input/Level1B.h" Imported: (null)
moduleImport Callback
moduleImport is called when there was an explicit module-import syntax.
Argument descriptions:
| Argument Name | Argument Value Syntax | Clang C++ Type | Description |
|---|---|---|---|
| ImportLoc | "(file):(line):(col)" | SourceLocation | The location of import directive token. |
| Path | "(path)" | ModuleIdPath | The identifiers (and their locations) of the module "path". |
| Imported | ((module name)|(null)) | const Module | The imported module; can be null if importing failed. |
Example::
- Callback: moduleImport
ImportLoc: "d:/Clang/llvm/clang-tools-extra/test/pp-trace/pp-trace-modules.cpp:4:2"
Path: [{Name: Level1B, Loc: "d:/Clang/llvmnewmod/clang-tools-extra/test/pp-trace/pp-trace-modules.cpp:4:9"}, {Name: Level2B, Loc: "d:/Clang/llvmnewmod/clang-tools-extra/test/pp-trace/pp-trace-modules.cpp:4:17"}]
Imported: Level2B
EndOfMainFile Callback
EndOfMainFile is called when the end of the main file is reached.
Argument descriptions:
| Argument Name | Argument Value Syntax | Clang C++ Type | Description |
|---|---|---|---|
| (no arguments) |
Example::
- Callback: EndOfMainFile
Ident Callback
Ident is called when a #ident or #sccs directive is read.
Argument descriptions:
| Argument Name | Argument Value Syntax | Clang C++ Type | Description |
|---|---|---|---|
| Loc | "(file):(line):(col)" | SourceLocation | The location of the directive. |
| str | (name) | const std::string | The text of the directive. |
Example::
- Callback: Ident Loc: "D:/Clang/llvm/clang-tools-extra/test/pp-trace/pp-trace-ident.cpp:3:1" str: "$Id$"
PragmaDirective Callback
PragmaDirective is called when start reading any pragma directive.
Argument descriptions:
| Argument Name | Argument Value Syntax | Clang C++ Type | Description |
|---|---|---|---|
| Loc | "(file):(line):(col)" | SourceLocation | The location of the directive. |
| Introducer | (PIK_HashPragma|PIK__Pragma|PIK___pragma) | PragmaIntroducerKind | The type of the pragma directive. |
Example::
- Callback: PragmaDirective Loc: "D:/Clang/llvm/clang-tools-extra/test/pp-trace/pp-trace-pragma.cpp:3:1" Introducer: PIK_HashPragma
PragmaComment Callback
PragmaComment is called when a #pragma comment directive is read.
Argument descriptions:
| Argument Name | Argument Value Syntax | Clang C++ Type | Description |
|---|---|---|---|
| Loc | "(file):(line):(col)" | SourceLocation | The location of the directive. |
| Kind | ((name)|(null)) | const IdentifierInfo | The comment kind symbol. |
| Str | (message directive) | const std::string | The comment message directive. |
Example::
- Callback: PragmaComment Loc: "D:/Clang/llvm/clang-tools-extra/test/pp-trace/pp-trace-pragma.cpp:3:1" Kind: library Str: kernel32.lib
PragmaDetectMismatch Callback
PragmaDetectMismatch is called when a #pragma detect_mismatch directive is read.
Argument descriptions:
| Argument Name | Argument Value Syntax | Clang C++ Type | Description |
|---|---|---|---|
| Loc | "(file):(line):(col)" | SourceLocation | The location of the directive. |
| Name | "(name)" | const std::string | The name. |
| Value | (string) | const std::string | The value. |
Example::
- Callback: PragmaDetectMismatch Loc: "D:/Clang/llvm/clang-tools-extra/test/pp-trace/pp-trace-pragma.cpp:3:1" Name: name Value: value
PragmaDebug Callback
PragmaDebug is called when a #pragma clang __debug directive is read.
Argument descriptions:
| Argument Name | Argument Value Syntax | Clang C++ Type | Description |
|---|---|---|---|
| Loc | "(file):(line):(col)" | SourceLocation | The location of the directive. |
| DebugType | (string) | StringRef | Indicates type of debug message. |
Example::
- Callback: PragmaDebug Loc: "D:/Clang/llvm/clang-tools-extra/test/pp-trace/pp-trace-pragma.cpp:3:1" DebugType: warning
PragmaMessage Callback
PragmaMessage is called when a #pragma message directive is read.
Argument descriptions:
| Argument Name | Argument Value Syntax | Clang C++ Type | Description |
|---|---|---|---|
| Loc | "(file):(line):(col)" | SourceLocation | The location of the directive. |
| Namespace | (name) | StringRef | The namespace of the message directive. |
| Kind | (PMK_Message|PMK_Warning|PMK_Error) | PPCallbacks::PragmaMessageKind | The type of the message directive. |
| Str | (string) | StringRef | The text of the message directive. |
Example::
- Callback: PragmaMessage Loc: "D:/Clang/llvm/clang-tools-extra/test/pp-trace/pp-trace-pragma.cpp:3:1" Namespace: "GCC" Kind: PMK_Message Str: The message text.
PragmaDiagnosticPush Callback
PragmaDiagnosticPush is called when a #pragma gcc diagnostic push directive is read.
Argument descriptions:
| Argument Name | Argument Value Syntax | Clang C++ Type | Description |
|---|---|---|---|
| Loc | "(file):(line):(col)" | SourceLocation | The location of the directive. |
| Namespace | (name) | StringRef | Namespace name. |
Example::
- Callback: PragmaDiagnosticPush Loc: "D:/Clang/llvm/clang-tools-extra/test/pp-trace/pp-trace-pragma.cpp:3:1" Namespace: "GCC"
PragmaDiagnosticPop Callback
PragmaDiagnosticPop is called when a #pragma gcc diagnostic pop directive is read.
Argument descriptions:
| Argument Name | Argument Value Syntax | Clang C++ Type | Description |
|---|---|---|---|
| Loc | "(file):(line):(col)" | SourceLocation | The location of the directive. |
| Namespace | (name) | StringRef | Namespace name. |
Example::
- Callback: PragmaDiagnosticPop Loc: "D:/Clang/llvm/clang-tools-extra/test/pp-trace/pp-trace-pragma.cpp:3:1" Namespace: "GCC"
PragmaDiagnostic Callback
PragmaDiagnostic is called when a #pragma gcc diagnostic directive is read.
Argument descriptions:
| Argument Name | Argument Value Syntax | Clang C++ Type | Description |
|---|---|---|---|
| Loc | "(file):(line):(col)" | SourceLocation | The location of the directive. |
| Namespace | (name) | StringRef | Namespace name. |
| mapping | (0|MAP_IGNORE|MAP_WARNING|MAP_ERROR|MAP_FATAL) | diag::Severity | Mapping type. |
| Str | (string) | StringRef | Warning/error name. |
Example::
- Callback: PragmaDiagnostic Loc: "D:/Clang/llvm/clang-tools-extra/test/pp-trace/pp-trace-pragma.cpp:3:1" Namespace: "GCC" mapping: MAP_WARNING Str: WarningName
PragmaOpenCLExtension Callback
PragmaOpenCLExtension is called when OpenCL extension is either disabled or enabled with a pragma.
Argument descriptions:
| Argument Name | Argument Value Syntax | Clang C++ Type | Description |
|---|---|---|---|
| NameLoc | "(file):(line):(col)" | SourceLocation | The location of the name. |
| Name | (name) | const IdentifierInfo | Name symbol. |
| StateLoc | "(file):(line):(col)" | SourceLocation | The location of the state. |
| State | (1|0) | unsigned | Enabled/disabled state. |
Example::
- Callback: PragmaOpenCLExtension NameLoc: "D:/Clang/llvm/clang-tools-extra/test/pp-trace/pp-trace-pragma.cpp:3:10" Name: Name StateLoc: "D:/Clang/llvm/clang-tools-extra/test/pp-trace/pp-trace-pragma.cpp:3:18" State: 1
PragmaWarning Callback
PragmaWarning is called when a #pragma warning directive is read.
Argument descriptions:
| Argument Name | Argument Value Syntax | Clang C++ Type | Description |
|---|---|---|---|
| Loc | "(file):(line):(col)" | SourceLocation | The location of the directive. |
| WarningSpec | (string) | StringRef | The warning specifier. |
| Ids | [(number)[, ...]] | ArrayRef<int> | The warning numbers. |
Example::
- Callback: PragmaWarning Loc: "D:/Clang/llvm/clang-tools-extra/test/pp-trace/pp-trace-pragma.cpp:3:1" WarningSpec: disable Ids: 1,2,3
PragmaWarningPush Callback
PragmaWarningPush is called when a #pragma warning(push) directive is read.
Argument descriptions:
| Argument Name | Argument Value Syntax | Clang C++ Type | Description |
|---|---|---|---|
| Loc | "(file):(line):(col)" | SourceLocation | The location of the directive. |
| Level | (number) | int | Warning level. |
Example::
- Callback: PragmaWarningPush Loc: "D:/Clang/llvm/clang-tools-extra/test/pp-trace/pp-trace-pragma.cpp:3:1" Level: 1
PragmaWarningPop Callback
PragmaWarningPop is called when a #pragma warning(pop) directive is read.
Argument descriptions:
| Argument Name | Argument Value Syntax | Clang C++ Type | Description |
|---|---|---|---|
| Loc | "(file):(line):(col)" | SourceLocation | The location of the directive. |
Example::
- Callback: PragmaWarningPop Loc: "D:/Clang/llvm/clang-tools-extra/test/pp-trace/pp-trace-pragma.cpp:3:1"
MacroExpands Callback
MacroExpands is called when ::HandleMacroExpandedIdentifier when a macro invocation is found.
Argument descriptions:
| Argument Name | Argument Value Syntax | Clang C++ Type | Description |
|---|---|---|---|
| MacroNameTok | (token) | const Token | The macro name token. |
| MacroDirective | (MD_Define|MD_Undefine|MD_Visibility) | const MacroDirective | The kind of macro directive from the MacroDirective structure. |
| Range | ["(file):(line):(col)", "(file):(line):(col)"] | SourceRange | The source range for the expansion. |
| Args | [(name)|(number)|<(token name)>[, ...]] | const MacroArgs | The argument tokens. Names and numbers are literal, everything else is of the form '<' tokenName '>'. |
Example::
- Callback: MacroExpands MacroNameTok: X_IMPL MacroDirective: MD_Define Range: [(nonfile), (nonfile)] Args: [a <plus> y, b]
MacroDefined Callback
MacroDefined is called when a macro definition is seen.
Argument descriptions:
| Argument Name | Argument Value Syntax | Clang C++ Type | Description |
|---|---|---|---|
| MacroNameTok | (token) | const Token | The macro name token. |
| MacroDirective | (MD_Define|MD_Undefine|MD_Visibility) | const MacroDirective | The kind of macro directive from the MacroDirective structure. |
Example::
- Callback: MacroDefined MacroNameTok: X_IMPL MacroDirective: MD_Define
MacroUndefined Callback
MacroUndefined is called when a macro #undef is seen.
Argument descriptions:
| Argument Name | Argument Value Syntax | Clang C++ Type | Description |
|---|---|---|---|
| MacroNameTok | (token) | const Token | The macro name token. |
| MacroDirective | (MD_Define|MD_Undefine|MD_Visibility) | const MacroDirective | The kind of macro directive from the MacroDirective structure. |
Example::
- Callback: MacroUndefined MacroNameTok: X_IMPL MacroDirective: MD_Define
Defined Callback
Defined is called when the 'defined' operator is seen.
Argument descriptions:
| Argument Name | Argument Value Syntax | Clang C++ Type | Description |
|---|---|---|---|
| MacroNameTok | (token) | const Token | The macro name token. |
| MacroDirective | (MD_Define|MD_Undefine|MD_Visibility) | const MacroDirective | The kind of macro directive from the MacroDirective structure. |
| Range | ["(file):(line):(col)", "(file):(line):(col)"] | SourceRange | The source range for the directive. |
Example::
- Callback: Defined MacroNameTok: MACRO MacroDirective: (null) Range: ["D:/Clang/llvm/clang-tools-extra/test/pp-trace/pp-trace-macro.cpp:8:5", "D:/Clang/llvm/clang-tools-extra/test/pp-trace/pp-trace-macro.cpp:8:19"]
SourceRangeSkipped Callback
SourceRangeSkipped is called when a source range is skipped.
Argument descriptions:
| Argument Name | Argument Value Syntax | Clang C++ Type | Description |
|---|---|---|---|
| Range | ["(file):(line):(col)", "(file):(line):(col)"] | SourceRange | The source range skipped. |
Example::
- Callback: SourceRangeSkipped Range: [":/Clang/llvm/clang-tools-extra/test/pp-trace/pp-trace-macro.cpp:8:2", ":/Clang/llvm/clang-tools-extra/test/pp-trace/pp-trace-macro.cpp:9:2"]
If Callback
If is called when an #if is seen.
Argument descriptions:
| Argument Name | Argument Value Syntax | Clang C++ Type | Description |
|---|---|---|---|
| Loc | "(file):(line):(col)" | SourceLocation | The location of the directive. |
| ConditionRange | ["(file):(line):(col)", "(file):(line):(col)"] | SourceRange | The source range for the condition. |
| ConditionValue | (true|false) | bool | The condition value. |
Example::
- Callback: If Loc: "D:/Clang/llvm/clang-tools-extra/test/pp-trace/pp-trace-macro.cpp:8:2" ConditionRange: ["D:/Clang/llvm/clang-tools-extra/test/pp-trace/pp-trace-macro.cpp:8:4", "D:/Clang/llvm/clang-tools-extra/test/pp-trace/pp-trace-macro.cpp:9:1"] ConditionValue: false
Elif Callback
Elif is called when an #elif is seen.
Argument descriptions:
| Argument Name | Argument Value Syntax | Clang C++ Type | Description |
|---|---|---|---|
| Loc | "(file):(line):(col)" | SourceLocation | The location of the directive. |
| ConditionRange | ["(file):(line):(col)", "(file):(line):(col)"] | SourceRange | The source range for the condition. |
| ConditionValue | (true|false) | bool | The condition value. |
| IfLoc | "(file):(line):(col)" | SourceLocation | The location of the directive. |
Example::
- Callback: Elif Loc: "D:/Clang/llvm/clang-tools-extra/test/pp-trace/pp-trace-macro.cpp:10:2" ConditionRange: ["D:/Clang/llvm/clang-tools-extra/test/pp-trace/pp-trace-macro.cpp:10:4", "D:/Clang/llvm/clang-tools-extra/test/pp-trace/pp-trace-macro.cpp:11:1"] ConditionValue: false IfLoc: "D:/Clang/llvm/clang-tools-extra/test/pp-trace/pp-trace-macro.cpp:8:2"
Ifdef Callback
Ifdef is called when an #ifdef is seen.
Argument descriptions:
| Argument Name | Argument Value Syntax | Clang C++ Type | Description |
|---|---|---|---|
| Loc | "(file):(line):(col)" | SourceLocation | The location of the directive. |
| MacroNameTok | (token) | const Token | The macro name token. |
| MacroDirective | (MD_Define|MD_Undefine|MD_Visibility) | const MacroDirective | The kind of macro directive from the MacroDirective structure. |
Example::
- Callback: Ifdef Loc: "D:/Clang/llvm/clang-tools-extra/test/pp-trace/pp-trace-conditional.cpp:3:1" MacroNameTok: MACRO MacroDirective: MD_Define
Ifndef Callback
Ifndef is called when an #ifndef is seen.
Argument descriptions:
| Argument Name | Argument Value Syntax | Clang C++ Type | Description |
|---|---|---|---|
| Loc | "(file):(line):(col)" | SourceLocation | The location of the directive. |
| MacroNameTok | (token) | const Token | The macro name token. |
| MacroDirective | (MD_Define|MD_Undefine|MD_Visibility) | const MacroDirective | The kind of macro directive from the MacroDirective structure. |
Example::
- Callback: Ifndef Loc: "D:/Clang/llvm/clang-tools-extra/test/pp-trace/pp-trace-conditional.cpp:3:1" MacroNameTok: MACRO MacroDirective: MD_Define
Else Callback
Else is called when an #else is seen.
Argument descriptions:
| Argument Name | Argument Value Syntax | Clang C++ Type | Description |
|---|---|---|---|
| Loc | "(file):(line):(col)" | SourceLocation | The location of the else directive. |
| IfLoc | "(file):(line):(col)" | SourceLocation | The location of the if directive. |
Example::
- Callback: Else Loc: "D:/Clang/llvm/clang-tools-extra/test/pp-trace/pp-trace-macro.cpp:10:2" IfLoc: "D:/Clang/llvm/clang-tools-extra/test/pp-trace/pp-trace-macro.cpp:8:2"
Endif Callback
Endif is called when an #endif is seen.
Argument descriptions:
| Argument Name | Argument Value Syntax | Clang C++ Type | Description |
|---|---|---|---|
| Loc | "(file):(line):(col)" | SourceLocation | The location of the endif directive. |
| IfLoc | "(file):(line):(col)" | SourceLocation | The location of the if directive. |
Example::
- Callback: Endif Loc: "D:/Clang/llvm/clang-tools-extra/test/pp-trace/pp-trace-macro.cpp:10:2" IfLoc: "D:/Clang/llvm/clang-tools-extra/test/pp-trace/pp-trace-macro.cpp:8:2"
Building pp-trace
To build from source:
- Read Getting Started with the LLVM System and Clang Tools Documentation for information on getting sources for LLVM, Clang, and Clang Extra Tools.
-
Getting Started with the LLVM System and Building LLVM with CMake give
directions for how to build. With sources all checked out into the
right place the LLVM build will build Clang Extra Tools and their
dependencies automatically.
- If using CMake, you can also use the
pp-tracetarget to build just the pp-trace tool and its dependencies.
- If using CMake, you can also use the